In recent years, a copper wire has been proposed as a bonding wire in place of a gold wire.
In Patent Document 1, there is disclosed a semiconductor device in which a copper-aluminum intermetallic compound is formed at a lunation interface between a wire and an electrode among semiconductor devices in which electrodes and leads of a semiconductor element are connected by a copper bonding wire, and led out. According to Patent Document 1, since a copper ball is brought into close contact with the electrode by forming a CuAl2 layer at a junction interface between the copper ball and the aluminum electrode, the reliability is improved from the viewpoint of corrosion resistance.